Thanks.
The wave editor just defines waves and saves them into a slot.
I script each level with javascript. Those scripts generates enemies, applies various AIs to a FSM of those enemies, and those AIs can also use any of the paths I definied. The scripts are very simple, and I can update them in the client on the fly. But I'm not quite sure if I require it, but I'm also thinking of putting some effort in a Level-Editor (but it's hard to design something simple that has the flexibility of scripting everything).
So I can switch waves off an enemy on the fly and I also manipulate them on the fly. For example I assign a path to 10 enemies, and than move the last point of the path so all enemies build a cool formation at the end of the wave
